. >> reporter: beyonce took the stage at president obama's inauguration this week and delivered what many called a memorable performance. >> i thought she did an excellent job, sang really well, passionate and i thought it was moving. moving to watch. >> reporter: but there are reports her singing wasn't what everyone thought. ♪ [ music ]♪ >> reporter: the controversy erupted on tuesday when a spokeswoman for the marine corps band said the singer used a prerecorded voice track instead of singing live. the marines later backed off that statement saying no one in the marine band is in a position to assess whether it was live or prerecorded. sources tell cbs news beyonce did sing and her mic was hot. but that she was matching her voice to a prerecorded track. it's not uncommon to prerecord inaugural music in case there's bad weather or other unexpected circumstances but temperatures were mild on inauguration day and the skies were clear. ♪ [ music ]♪ >> reporter: it was a much colder day four years ago when cellist yo-yo ma and violinist yitzhak perleman used a recording and ano